Qbservable.DefaultIfEmpty<TSource> Method (IQbservable<TSource>)
Returns the elements of the specified sequence or the type parameter's default value in a singleton sequence if the sequence is empty.
Namespace: System.Reactive.Linq
Assembly: System.Reactive.Providers (in System.Reactive.Providers.dll)
public static IQbservable<TSource> DefaultIfEmpty<TSource>( this IQbservable<TSource> source )
Type Parameters
- TSource
The type of source.
Parameters
- source
- Type: System.Reactive.Linq.IQbservable<TSource>
The sequence to return a default value for if it is empty.
Return Value
Type: System.Reactive.Linq.IQbservable<TSource>A queryable observable sequence that contains the default value for the TSource type if the source is empty; otherwise, the elements of the source itself.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IQbservable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see https://msdn.microsoft.com/en-us/library/bb384936(v=vs.103).aspx or https://msdn.microsoft.com/en-us/library/bb383977(v=vs.103).aspx.
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